Adult: 5-10 mg via IM inj as a single dose, may be repeated after 20 minutes if necessary. Max: 20 mg daily. Elderly: Dose reduction may be required.
Intravenous Acute dystonia
Adult: 5-10 mg via IV inj; higher doses may be necessary. Elderly: Dose reduction may be required.
Oral Drug-induced extrapyramidal symptoms
Adult: Initially, 2.5 mg tid, may be increased gradually in increments of 2.5 mg daily until optimum clinical response is achieved. Usual maintenance dose: 10-30 mg daily. Discontinue treatment after 3-4 months and observe patient for recurrence of drug-induced extrapyramidal symptoms; procyclidine may be reintroduced if extrapyramidal symptoms recur. Elderly: Dose reduction may be required.
Oral Parkinsonism
Adult: Initially, 2.5 mg tid, may be increased gradually in increments of 2.5-5 mg daily at 2-3-day intervals until optimum clinical response is achieved. Usual maintenance dose: 15-30 mg daily. Doses up to 60 mg daily may be required in some cases. Elderly: Dose reduction may be required.
Patient with CV disease (e.g. tachycardia, cardiac arrhythmia, hypertension, hypotension); prostatic hypertrophy; mental disorders; predisposition to angle-closure glaucoma. Use in hot weather or during exercise. Not recommended for use in patient with tardive dyskinesia (unless with concomitant Parkinson's disease or tardive dystonia). Procyclidine has the potential to be abused; caution should be exercised before use. Avoid abrupt withdrawal. Renal and hepatic impairment. Elderly. Pregnancy and lactation.
Adverse Reactions
Significant: CNS effects including restlessness, confusion, and hallucinations (particularly at higher doses); may cause anhidrosis and hyperthermia (particularly in patients exposed to hot environments); may precipitate psychotic episodes (particularly in patients with mental disorders). Eye disorders: Blurred vision. Gastrointestinal disorders: Dry mouth, constipation, nausea, vomiting, gingivitis. Nervous system disorders: Dizziness, memory impairment. Psychiatric disorders: Agitation, anxiety, nervousness, disorientation. Renal and urinary disorders: Urinary retention. Skin and subcutaneous tissue disorders: Rash.
Patient Counseling Information
This drug may cause dizziness, confusion, disorientation and blurred vision, if affected, do not drive or operate machinery.
Monitoring Parameters
Monitor heart rate and anticholinergic effects (e.g. CNS, bowel and bladder function).
Overdosage
Symptoms: Stimulant effects (e.g. agitation, restlessness and confusion with severe sleeplessness lasting up to ≥24 hours), tachycardia, widely dilated pupils which are unreactive to light, visual hallucinations, auditory hallucinations, disorientation, euphoria, anxiety, aggressive behaviour. In massive overdoses, CNS depression (e.g. somnolence, reduced consciousness, coma) may occur. Management: May give activated charcoal within 1-2 hours (or possibly longer) of ingestion to reduce absorption. Gastric lavage may be considered if appropriate. In case of convulsions, may administer diazepam inj.
Drug Interactions
Enhanced anticholinergic effects with MAOIs or other drugs with anticholinergic activity (e.g. TCAs, amantadine, phenothiazines, antihistamines, memantine, clozapine). May decrease the absorption and therapeutic effect of sublingual or buccal nitrate tab. Reduced therapeutic response with cholinergic drugs (e.g. tacrine). Increased plasma concentration with paroxetine. May reduce the therapeutic effect of levodopa due to increased gastric emptying time. May antagonise the gastrointestinal effects of cisapride, domperidone and metoclopramide. May reduce the absorption of ketoconazole.
Action
Description: Mechanism of Action: Procyclidine, a tertiary amine antimuscarinic agent, is believed to act by inhibiting excess acetylcholine at cerebral synapses, thus blocking its excitatory effects at the muscarinic receptor. Onset: 45-60 minutes. Duration: Significant autonomic effects: Up to 12 hours. Pharmacokinetics: Absorption: Absorbed from the gastrointestinal tract. Bioavailability: Approx 75%. Time to peak plasma concentration: Approx 1.1 hours. Distribution: Volume of distribution: 1 L/kg. Metabolism: Metabolised in the liver (approx one-fifth of oral dose), mainly by CYP450 isoenzymes, then via conjugation with glucuronic acid. Excretion: Via urine (mainly as metabolites; as unchanged drug in small amount). Elimination half-life: Approx 12 hours.
Chemical Structure
Procyclidine Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 4919, Procyclidine. https://pubchem.ncbi.nlm.nih.gov/compound/Procyclidine. Accessed Mar. 26, 2025.